Review: Derek Parfit’s “Reasons and Persons”

by Miles Raymer


Every now and then, I come across a book that painfully reveals the limitations of my intellect and critical faculties. Derek Parfit’s Reasons and Persons is one such book. This dense, esoteric text coaxed me right up to the cliff’s edge of my philosophical comprehension, and then shoved me off without ceremony. Even so, I had a few intriguing concepts to contemplate on the way down.

Although I probably lack the raw intelligence to grapple appropriately with the structure of Parfit’s arguments, that wasn’t my only hindrance. I studied philosophy as an undergraduate, but belonged to a relatively untraditional philosophy department and received little training in logic and the analytic style. I am ill-equipped, therefore, to parse the “mathy” approach Parfit brings to moral philosophy. Take this passage for example:

The argument appeals to the fact that S would tell us to make ourselves believe that it is rational to keep our promises, even when we know that this will be worse for us. Call this belief B. B is incompatible with S, since S claims that it is irrational to keep such promises. Either S is the true theory about rationality, or it is not. If S is true, B must be false, since it is incompatible with S. If S is not true, B might be true, but S cannot support B, since a theory that is not true cannot support any conclusion. In brief: if S is true, B must be false, and if S is not true, it cannot support B. B is either false, or not supported. So, even if S tells us to try to believe B, this fact cannot support B. (19, emphasis his)

This line of reasoning is perfectly valid, and even lucid in its fashion. However, it is exactly the kind of writing that makes me want to assume the fetal position and emerge only when all philosophical questions have been resolved and humanity is lounging in the Elysium of Perfect Enlightenment. Reasons and Persons is rife with more and less complicated iterations of the style shown above, and exceeds 500 yawn-inducing pages (including appendices).

Parfit is also fond of wacky thought experiments. These land with varying degrees of impact, but more often than not feel too divorced from real-world circumstances to provide weighty insight. Take his proposition of Two Hells:

In Hell One, the last generation [of humans] consists of ten innocent people, who each suffer great agony for fifty years. The lives of these people are much worse than nothing. They would all kill themselves if they could. In Hell Two, the last generation consists not of ten but of ten million innocent people, who each suffer agony just as great for fifty years minus a day. (393, emphasis his)

Parfit goes on to explore in great depth the question of which of these Two Hells is less desirable, uncovering along the way some interesting observations about our moral intuitions. But there are two problems with this approach. First, the Two Hells are both so utterly implausible that I immediately become suspicious of any conclusions Parfit draws from their comparison, even if his reasoning is sound. Such conclusions may be valid within the conceptual boundaries of the thought experiment, but does that mean they are equally valid in the real world? I doubt it. Second, most or all of his supportable conclusions could also be reached using scientific evidence, which would bolster their credibility and obviate the need for elaborate logical puzzles that often confuse more than they clarify.

I felt that both of these problems were pervasive throughout the book. In Parfit’s defense, our scientific understanding of moral reasoning is much more developed in 2018 than it was in 1987, but even so that doesn’t reflect well on the book’s longevity. As a reviewer, I can’t in good conscience recommend this book when many or all of the same findings can be accessed elsewhere in more empirically-grounded and reader-friendly texts. Conversely, readers interested in the history of philosophy and/or the analytic tradition will likely find this book both useful and engaging. As far as I can tell, a majority of Parfit’s main conclusions have withstood the test of time, even if they may be in need of minor revision.

As the title suggests, Parfit is concerned with reasons for action and the persons who hold those reasons. His excellent “Concluding Chapter” provides a succinct summary:

My two subjects are reasons and persons. I have argued that, in various ways, our reasons for acting should become more impersonal. Greater impersonality may seem threatening. But it would often be better for everyone. (443, emphasis his)

To the extent I was able to understand this book, I feel that Parfit succeeded in making his case for a more impersonal way of deciding how we ought to live. In this view, our reasons for acting ought to derive legitimacy from the kinds of experiences we seek (or that we desire for others), rather than from the kinds of persons we perceive ourselves to be. Stated another way, the question of what experience(s) an action is likely to produce takes precedence over the question of what type of person(s) should act in such a way.

Parfit cleverly reveals many flaws in our natural intuitions about personal identity, casting doubt on the longstanding notion that identity formation is the key to ethical living. His “Reductionist View” of the self aligns neatly with modern definitions of personhood developed by psychologists and neuroscientists:

The truth is very different from what we are inclined to believe. Even if we are not aware of this, most of us are Non-Reductionists. If we considered my imagined cases, we would be strongly inclined to believe that our continued existence is a deep further fact, distinct from physical and psychological continuity, and a fact that must be all-or-nothing. This is not true. (281)

On the Reductionist View…It is more plausible to focus, not on persons, but on experiences, and to claim that what matters morally is the nature of these experiences…This principle ignores the boundaries between lives, or the separateness of persons. (446)

Parfit doesn’t deny the physical distinction between human bodies, but does challenge the assumption that this distinction signifies a radical or unbridgeable difference. If experience is the common currency we use to determine the ethical value of an act, each experiencing being has a legitimate position to defend and a perspective from which to advocate. Personal identity, with its tendency to rely on superficial physical features and historical, national, and/or tribal associations, provides no such common currency and often pits one group of persons against another. For these reasons, Parfit’s advocacy for a more impersonal ethics rings true for me.

Another problem Parfit tackles is the thorny issue of our collective contribution to slow-moving catastrophes. By invoking the “Harmless Torturers,” one of the book’s most effective thought experiments, Parfit propounds a form of rational altruism that encourages us to look beyond the immediately-perceptible results of our behaviors:

In the Bad Old Days, each torturer inflicted severe pain on one victim. Things have now changed. Each of the thousand torturers presses a button, thereby turning the switch once on each of the thousand instruments. The victims suffer the same severe pain. But none of the torturers makes any victim’s pain perceptibly worse. (80)

When all the Harmless Torturers act, each is acting very wrongly. This is true even though each makes no one perceptibly worse off. The same could be true of us. We should cease to think that an act cannot be wrong, because of its effects on other people, if this act makes no one perceptibly worse off. Each of our acts may be very wrong, because of its effects on other people, even if none of these people could ever notice any of these effects. Our acts may together make these people very much worse off. (83, emphasis his)

Parfit explicitly deploys this thought experiment to help us properly frame some of our most pressing modern problems:

They [the Harmless Torturers] know that, though none of them makes any perceptible difference, they together inflict on their victims severe pain. There are countless actual cases of this kind. In these cases it is true, of the act of each, that its effects on others are trivial or imperceptible. We mistakenly believe that, because this is true, the effects of our acts cannot make them wrong. But, though each act has trivial effects, it is often true that we together impose great harm on ourselves or others. Some examples are pollution, congestion, depletion, inflation, unemployment, a recession, over-fishing, over-farming, soil-erosion, famine, and overpopulation.

While we have these false beliefs, our ignorance is an excuse. But after we have seen that these beliefs are false, we have no excuse. If we continue to act in these ways, our acts will be morally wrong. Some may be as bad as the acts of the Harmless Torturers. (444)

In this era of globalization, climate change, and mass social media, never before have so many humans had the ability to perform actions with consequences that are obfuscated or concealed completely. It is easy to argue, as Paul Bloom and Matthew Jordan recently suggested, that contemporary life has made Harmless Torturers of us all.

Reasons and Persons leaves me with little doubt that something positive can be gained by assuming a more impersonal ethics that seeks to prioritize desirable experiences and to minimize harm, especially when the results of harmful behaviors are hidden from direct observation. Still, this is a tough sell for a virtue ethicist such as myself. The cultivation of moral personhood is the central focus of virtue ethics, a practice to which I have devoted a huge portion of my mental energy.

While Parfit’s diminished sense of personal identity may produce more ethical behavior in some circumstances, I continue to believe that the cultivation of virtuous identities can do the same. Ultimately, reasons and identities can both be directed toward moral or immoral ends. We ought, therefore, to approach each ethical challenge as it arises, and be willing to apply impersonal or personalized ethics according to our best guesses about which will produce the best outcome. While depersonalizing our moral calculus may be the ticket in some circumstances (such as professional or political arenas), an intimately personal ethics may be most efficacious in others (such as relations with friends and family).

Putting aside these difficult questions, we can rest assured that Parfit’s embrace of Reductionism exerted a powerful and positive effect, at least for him personally and presumably for many of his readers:

Is the truth depressing? Some may find it so. But I find it liberating, and consoling. When I believed that my existence was such a further fact, I seemed imprisoned in myself. My life seemed like a glass tunnel, through which I was moving faster every year, and at the end of which there was darkness. When I changed my view, the walls of my glass tunnel disappeared. I now live in the open air. There is still a difference between my life and the lives of other people. But the difference is less. Other people are closer. I am less concerned about the rest of my own life, and more concerned with the lives of others. (281)

Rating: 4/10